.alpha.-Santalene has been synthesised from .pi.-bromotricyclene by converson into Grignard's compound followed by condensation with dimethylallyl mesitoate (E. J. Corey, S. W. Chow and R. A. Scherrer, J. Amer. chem. Soc., 1957, 79, 5773) or by extension of the chain in several stages (S. Y. Kamat, K. K. Chakravarti and S. C. Bhattacharyya, Tetrahedron, 1967, 23, 4487) or by the condensation of .pi.-iodotricyclene with .pi.-dimethylallyl nickel (E. J. Corey and M. F. Semmelhack, J. Amer. chem. Soc., 1967, 89, 2755).
.alpha.-Santalol has been synthesised by oxidising .alpha.-santalene with selenium oxide (V. M. Sathe, M. V. Kadival, K. K. Chakravarti and S. C. Bhattacharyya, Indian J. Chem., 1964, 4, 393) or from .pi.-bromotricyclene by building the chain in several stages (J. Colonge, G. Descotes, J. Bahurel and A. Menet, Bull. Soc. chim. France, 1966, page 374; S. Y. Kamat, K. K. Chakravarti and S. C. Bhattacharyya, Tetrahedron, 1967, 23, 4487; R. G. Lewis, D. H. Gutstavon and W. F. Erman, Tet. Letters, 1967, 401). These syntheses are not stereoselective.
The function carried by the terminal carbon atom of the chain appears in the cis- and in the trans-position. E. J. Corey et al. introduced new methods for synthesising cis-allyl alcohols and were successful in preparing .alpha.-santalol by stereoselective syntheses.